Operation
13
Show Strip Chart
You can use the Strip Chart window to display a characteristic spectrum value as a
function of another value for all spectra in the list. The most common task is to display
the temporal evolution of a characteristic value. This window can be kept open while
taking new spectra to see the changes as they happen.
In the lower left side of the Strip Chart window, you can choose which values to assign to
the x and y axis of the chart. You can choose all numerical values that are displayed in the
Properties Panel in the main window. If you want to view the temporal evolution of a
spectrum into a number. So for example,
value are used for the corresponding axis.
In the Strip Chart diagram, the currently selected spectrum is marked by a slightly larger
point. Points corresponding to spectra that are currently not visible in the main window
are drawn in a lighter red color.
Show Loupe
This opens a window with a magnified display of the spectrum around the mouse
pointer. It may be used in order to study small features in the spectrum as an alternative
to zooming in.
3.8
Absorption, Reflection and Transmission Measurements
Principle
In absorption, reflection and transmission spectroscopy you direct light from a
broadband light source onto a sample. Then you take a spectrum
𝐼(λ)
of the light that is
transmitted through or reflected from the sample. In order to get meaningful results that
are independent of the light source, you also take a spectrum of the light source
𝐼
0
(λ)
as
a reference.
The spectral transmittance
𝑇(λ)
or reflectance is then simply the fraction of transmitted
or reflected light:
𝑇(λ) =
𝐼(λ)
𝐼
0
(λ)
This formula gives values in the range between 0 and 1. The transmittance is usually
written as a percentage. The spectral absorbance
𝐴(λ)
is defined as:
𝐴(λ) = log
𝐼
0
(λ)
𝐼(λ)
